1. Field of the Invention
The present invention relates to a threading device of a sewing machine, which has a very simple structure and which assists an operation of passing a thread through the needle hole of a needle.
2. Description of the Related Art
Conventionally, various threading devices have been proposed, which pass threads through the needle hole of a needle attached to a needle bar of a sewing machine. For example, the threading device disclosed in Japanese Patent Application Laid-open No. H7-284588 has a threading hook having a hook portion formed at a distal end so as to grab a thread. This threading hook grabs a thread stretched in a tense state near the needle hole of the needle by a thread holding tool and is drawn from the needle hole to perform a threading operation.
In a threading device, the threading hook drawn from a needle hole is moved upward from the needle hole such that the thread is reliably pulled out of the needle hole. With this upward movement, the thread comes off from a claw portion of the hook and the threading operation is thus completed. An example of a sewing machine having this type of mechanism is disclosed in Japanese Patent Application Laid-open No. H7-284588.